Still use Internet Explorer? Don’t

What you need to know about the latest Internet security threat

A security flaw in Microsoft’s
MSFT, -0.38%
Internet Explorer browser revealed this weekend “could lead to the complete compromise of an affected system,” the Department of Homeland Security says. Officials recommend that users use alternative browsers until Microsoft fixes the issue and releases software updates.

The vulnerable Internet Explorer versions make up more than 56% of the browser market, according to NetMarketShare.com. And those who use the estimated 300 million machines running Windows XP won’t even be getting a fix: Microsoft stopped supporting XP on April 8, meaning there won’t be software updates. (Microsoft does offer a separate “toolkit” to help shield computers from hackers and says that software can mitigate attacks in this scenario.)

Whether or not Internet Explorer was already dead depends on which data you look at. NetMarketShare says Internet Explorer dominates the browser world, reigning over 58% of the market, with Google’s Chrome and Firefox near-tied at 17%. Other estimates, though, give Internet Explorer a lot less love. The web development site W3Schools.com estimated that Chrome ran on the lion’s share of devices in March, at 58%, with Firefox trailing at 26% and Internet Explorer sitting at less than 10%.

Hacking attacks stemming from the flaw have so far been limited and are targeting specific groups and firms, Satnam Narang, a security response researcher at Symantec, says. But with the vulnerability now public, others could exploit it as well — and through stealthier means than phishing scams that ask users to click on a link.

“They’re essentially inserting this malicious code onto a website and if you happen to visit that website at the time when that malicious code is there, your computer is at risk,” Narang says.

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